Conventional control systems for supplying pulverized coal to furnaces, such as rotary kilns, control the temperature of the inlet gas to a pulverizer or dryer based on a fixed outlet temperature of the coal and air mixture leaving the pulverizer.
For example, U.S. Pat. No. 3,050,018 discloses a control system applicable for rotary kilns and metallurgical furnaces whereby, the temperature of the coal and air mixture leaving the pulverizer is maintained at a selected value and the temperature of the air entering the pulverizer is changed to maintain a uniform exit temperature.
However, controlling the temperature of the inlet gas to the pulverizer or dryer based on the measured moisture removed from the coal or the actual moisture in the coal transported to burner is a more accurate controlling mechanism for various types of coal, which characteristically have different amounts of moisture. Fluctuations of coal moisture content to burners of a coal gasification reactor, hereinafter referred to as a gasifier, are detrimental to gasifier performance. For example, fluctuations cause inefficient gasification of fuel within the gasifier. The efficient gasification of a fuel depends on the ratios of carbon, hydrogen, and oxygen in the reactor. Coal consists primarily of carbon, hydrogen, oxygen, water and non-combustible materials. For a given coal source the carbon, hydrogen, oxygen and non-combustible materials are relatively constant but the water content can vary widely. Since water is comprised of hydrogen and oxygen, the water content of the reactor feed must be measured and controlled for efficient gasification.
The present invention is directed to overcoming this problem in the prior art.
Applicants are not aware of any prior art which, in their judgment as persons skilled in this particular art, would anticipate or render obvious the present invention. However, for the purpose of fully developing the background of this invention, and establishing the state of requisite art, the following art is set forth: U.S. Pat. No. 4,430,963.